1. Field of the Invention
This invention is directed to an interface between a flexible shaft and circuit interrupting device and more particularly to such an interface between a linearly moving rod of the flexible shaft and a rotary mechanism which interacts with the handle of the circuit breaker.
2. Description of the Prior Art
Molded case circuit breakers are well known in the art. Examples of such circuit breakers are disclosed in U.S. Pat. No. 4,679,018, for instance. Such circuit breakers are used to protect electrical circuitry from damaged due to an overcurrent condition. Molded case circuit breakers include a pair of separable contacts, which may be operated either manually by way of a handle disposed on the outside of the case or automatically in response to an overcurrent condition.
For a variety of reasons, such as operator safety, for example, circuit interrupters are often mounted behind a panel cover or behind a door in a cabinet. Typically, in these installations, the handles of the circuit interrupters are not directly accessible without opening the cover or door. In some of these installations a remote handle mechanism is mounted on or near the opposite side or exterior of the panel or door and a mechanical linkage is used to interconnect the remote handle mechanism with the circuit interrupter handle. Examples of such mechanisms can be found in U.S. Pat. No. 5,493,084 assigned to the assignee of the present invention entitled "Door Release for Circuit Interrupter Rotary Handle Mechanism". In this case there is a relatively ridged linkage between the circuit interrupter handle the remotely mounted handled. Another example maybe found in U.S. Pat. No. 5,422,453 which teaches an actuator for displacing the toggle or handle of a circuit interrupter, in particularly this includes a pair of space, abutment surfaces for bearing against the handle along an arcuate path coincident with the motion of the handle. Still a third example may be found in U.S. Pat. No. 5,428,196 entitled "Flexible Shaft Interface for Circuit Interrupter" also assigned to the same assignee as the present application. Here is taught a interface between an flexible shaft and a circuit interrupting device and more particularly to an interface between a linearly movable rod of the flexible shaft and the handle of the circuit breaker. Reference may also be made to Eaton publication SA12092 July 94-TLG1043 entitled, "Flex Shaft.TM. Flange Mounted Handle Mechanism". Still another example maybe found in a publication entitled, "Westinghouse Series C.RTM. M-Frame External Accessories" 29-120M January, 1995. In the latter three examples a flexible cable is provided between the external handle and the circuit breaker handle. This is advantageous for allowing easy disposal of the circuit breaker on the inside of the cabinet. Since there are no ridged interconnections between the external handle and the circuit breaker handle a broad range of locations is possible inside of the circuit breaker cabinet for placement of the circuit interrupter.
Referring now to the drawings and FIG. 1 in particular, a prior art circuit interrupter system of the kind having a circuit interrupter disposed within a cabinet and a remote, exteriorly mounted operating handle with intermediate sheathed drive or two-piece cable is depicted. In particular there is provided a cabinet 10 having a back wall 12 and front wall or door 14. A remote operator handle 16 is provided on the front wall or door 14, which is interconnected by way of a sheathed, flexible cable 18 to a circuit breaker 20 mounted on the back wall 12. A transfer mechanism 22 is provided on the generally flat front face of the circuit breaker or interrupter 20. It includes a fixed base plate 24, which is attached to the front of the breaker 20 and sliding movable part 26, which is interconnected with the inner drive member of the cable 18. The breaker handled is captured in the movable part 26, so that as the operating handle 16 on the front wall is actuated to either open or close the circuit breaker, the drive member of the cable 18 moves the movable part 26 of the transfer mechanism 22 to cause the breaker or circuit interrupter handle 28 to move to open or close the circuit breaker separable main contacts as required.
Although the foregoing have many advantages, they do have certain disadvantages. One disadvantage lays in the fact that all of the mechanisms taught for interconnecting a flexible cable between an external handle and the internal handle of the circuit breaker rely upon centrally locating the cable interface on the front of the circuit breaker. Although this has the advantage of placing the longitudinally moving drive member of the cable immediately over the handle so as to reduce lateral torsion, it generally takes up significant cabinet space. It would be advantageous, if a means could be found for mounting a significant portion of the interface on the side of the circuit breaker thus freeing up more space in front of the face of the circuit breaker. But this will eliminate or greatly reduce the effect of sideways torsion on the handle which is usual for such an arrangement.